1. Field of the Invention
This invention relates generally to solid state disks and particularly to addressing schemes used by solid state disks.
2. Description of the Prior Art
With the advent of the popularity of solid state drives (SSDs) and exponential growth of network content, the emergence of all-flash storage systems such as, SSD array, or storage appliances has been realized. These systems or appliances are either directly attached to a server via the Peripheral Component Interconnect Express (PCIe) or Serial Attached SCSI (SAS) or network attached via some high speed, high bandwidth network such as 10 Giga bit Ethernet (10 GbE). These storage units may include arrays of one or more SSD to meet requisite capacity and performance.
One of the problems facing the foregoing arrangement is a bottle neck created between the host and the storage units in that hosts may not utilize the array of SSDs evenly therefore not operating at their optimum performance. For general consumer applications, such as hand-held devices, this arrangement works well. However, in more sophisticated applications, such as Redundant Array of Independent Disks (RAID), employing numerous SSDs, performance of the system is clearly hindered.
Another problem with current techniques is wear leveling. As readily known to those in the art, the SSD is addressed by a host using logical block addresses (LBAs) and physical block addresses (PBAs). The LBAs are ultimately correlated with PBAs, the latter of which identifies a physical location within a SSD. To this end, if a series of locations identified by LBAs belonging to a particular set of SSDs in the array is written and then re-written and the remaining LBA-identified locations in the rest of the SSD is not as frequently written and re-written, the SSDs that are written and re-written experience more wear than those that are not written or less frequently written. Obviously, the latter scenario is undesirable.
Thus, there is a need for a high performance storage system with improved performance and wear leveling.